In the UK and NZ, the vaccine is only given to those at-risk from Chickenpox. Children don't receive it as a matter of policy, and I don't believe adults who've never caught the disease are normally offered it, either.

One of the reasons/theories I've heard for this, is that if you've had Chickenpox, you are at-risk for Shingles -- which is often extremely painful and difficult to overcome. However, if you are regularly exposed to Chickenpox, your immune-system gets "reawakened" to the virus, therefore can more-quickly recognise and fight-off a recurrance, before it becomes Shingles.

One of the easiest ways to aid this exposure is to keep the virus active, but under-control, in the community. This has a useful side-effect of the community also being aware and more-knowledgeable about the disease, too.

Another argument I've heard against the vaccine is that it's simply not possible to get rid of Chickenpox totally -- it's _highly_ infectious, and the infectious stage is before symptoms appear, etc -- but the vaccine gives a false sense of security of protection, perhaps in the same way as everyone thinks they're safe from Smallpox, Hepatitis, Ebola, etc because we worked so hard to get rid of or control it.